The present invention relates to the sorting of mail pieces on a printing press.
A prior art sorting method is described with reference to FIG. 1. On an offset web press, a web 10 of printable material is printed with static content by press rollers 11 (e.g., an offset or blanket cylinder and an impression cylinder) to generate a printed web 10′ having sequential sections later cut into individual mail pieces 12. In other words, the section of the web 10 corresponding to each mail piece 12 is printed with the same set of text and/or graphics by the press rollers 11. One or more ink jet printers 14 are provided and controlled by a controller 16 to print variable information, which may include, for example, a recipient's address on each section of the printed web 10′ corresponding to an individual mail piece 12. A slitter unit 17 can slit the printed web 10′ longitudinally along the length to provide two or more parallel web sections. Furthermore, a cutter unit 18, such as a rotary cutter, can convert the printed web 10′ into individual mail pieces 12 by cutting the printed web 10′ at various locations along the web.
In some circumstances, the mail pieces 12 produced on the press are enveloped mail pieces (i.e., the mail pieces 12 comprise both a printed insert and an envelope). For example, a web 10a of envelope stock (which can be printed by additional press rollers 11a to form a printed envelope web 10a′) can be fed to the slitter unit 17 along with the first printed web 10′. The envelope stock is either printed with variable information (e.g., recipient's address) at an ink jet printer 20 as directed by the controller 16 or punctured with a die to form windows in the envelope stock, allowing variable print on the portions of the first printed web 10′ to show through when those portions of the first printed web 10′ are received in the envelopes. If enveloped on press, envelopes are built around individual portions of the first printed web 10′ at a folder 22 between the slitter unit 17 and the cutter unit 18. The folder 22 can include one or more die cutters (not shown) for cutting the printed web 10′ into discrete parts or sections. A folding mechanism in the folder 22 wraps the printed envelope web 10a′ around the first printed web 10′, or the discrete sections cut from the web, and the cutter unit 18 cuts the printed envelope web 10a′ into discrete parts or sections to form the discrete mail pieces 12.
Regardless of whether they are enveloped, the mail pieces 12 are assembled into shingled streams (a portion of each mail piece 12 rests on the adjacent piece 12) and transported by delivery tables 26 made up of multiple conveyors run at different speeds. As shown in FIG. 1, the shingled streams of mail pieces 12 are sent to end-of-line conveyors 30 where a team of workers 32 handles and removes the mail pieces 12. A pneumatically-actuated finger 34 along each delivery table 26 can be actuated by the controller 16 to identify batches of mail pieces 12 by creating increased gaps between predetermined adjacent mail pieces 12 of each shingled stream. These increased gaps identify bundle and tray breaks for the workers 32 that stack and remove the mail pieces 12. Bundle breaks identify the end of a mail group of mail pieces 12 to be associated together in a bundle 36 (e.g., a group of mail pieces 12, smaller than a standard-sized mail tray 40, belonging to a certain zip code or zip code grouping, postal service carrier route, etc.). Tray breaks identify the end of a group of mail pieces 12 that will fit into a single mail tray 40. The bundle and tray breaks for controlling the fingers 34 may be triggered by the controller 16 according to the same mail file that controls the address printing at the variable printer(s) 14, 20.
Even with the controller-operated fingers 34 marking bundle and tray breaks, multiple workers 32 are required at the end-of-line conveyors 30 to keep pace with the printing press, which may output 50,000 to 75,000 mail pieces per hour. The first worker 32A at each end-of-line conveyors 30 identifies the bundle breaks and adjusts the shingled group of mail pieces 12 into a horizontally-stacked bundle formation before placing the mail pieces 12 into a tray 40. The next worker 32B applies straps 44 to each bundle 36, if required. The last worker 32C on each end-of-line conveyor 30 transports the mail trays 40 into a skid 48 for eventual transport away from the end-of-line conveyor 30. The skids 48 may be transported by another worker to a shipping dock for direct shipment out of the printing facility to a postal service facility, or to a sorting device within the printing facility where the bundles 36 of mail pieces 12 are commingled with mail pieces from other presses to achieve greater postal service discounts.
In addition to marking bundle and tray breaks, the controller-operated fingers 34 can also be used to identify certain mail pieces 12 for removal. These mail pieces 12 may be identified somewhere along the press as being defective or may be generated as sample pieces in a controlled “book pull” operation for the press operator to visually monitor quality control or for providing to the customer of the print job (i.e., the official sender of the mail pieces 12). However, any of the mail pieces 12 identified as defective or samples must still be manually separated from the mail stream and directed to a trash bin or special collection area by a worker 32.
Automated devices that mark bundle and tray breaks have been incorporated into off-press mail sorting systems, such as in-line inserters, which create a mail stream of mail pieces by discharging mail pieces (printed on and transported from multiple presses) from a series of hoppers. These systems generally operate under 25,000 pieces per hour, and the stream of mail pieces is a non-shingled stream (i.e., the individual mail pieces are spaced apart along the direction of conveyance). An example of such an off-line device is the Mailstream Productivity Series high-speed mail inserter available from Pitney Bowes. A controller that controls the discharge of the various mail pieces from the various hoppers to create mail groups for attaining postal discounts can also mark bundle and tray breaks for identification by a worker. For example, end-of-bundle and end-of-tray mail pieces can be marked with different colored ink in a predetermined inconspicuous location for identification by the worker. On the other hand, a physical offset can be created among a stack of mail pieces to identify bundle and tray breaks. In one offsetting method, the end-of-bundle and end-of-tray mail pieces are positioned alongside a uniform stack of mail pieces, but positioned to have an edge visible out of registration with the rest of the stack. In another offsetting method, an entire stack will have a registration edge offset from that of the next sequential stack formed by the stacker such that each different stack created corresponds to a predetermined batch (i.e., for a single bundle or a single tray).